We evaluated the sensitivity and specificity of Technetium-99m (Tc-99m)-whi
te blood cell (WBC) for identifying terminal ileum inflammation in children
with Crohn's disease (CD). In 40 children, total colonoscopy was done with
in a few days of a Tc-99m-WBC scan carried out to evaluate the inflammation
in children with CD. In 38 patients the intensity and the location of infl
ammation shown on the Tc-99m-WBC scan of the colon were similar to the biop
sy result of the colonoscopy. The sensitivity of the Tc-99m-WBC scan was 97
% in assessing colonic inflammation compared with colonoscopy. The Tc-99m-W
BC scan allowed evaluation of inflammation in the terminal ileum in 21 pati
ents in whom the endoscopist did not cannulate the terminal ileum. Of the 1
9 patients in whom the terminal ileum was visualized endoscopically (14) or
surgically (5), the Tc-99m-WBC scan findings showed a similar degree of in
flammation in 17. The Tc-99m-WBC scan was abnormal in 10 of these 21 childr
en in whom the gastroenterologist did not reach the terminal ileum. In thes
e children with no ileoscopy the results of the Tc-99m-WBC scan were consis
tent with the laboratory values, the gastroenterologist's clinical assessme
nt and with long-term clinical followup. Finally, the Tc-99m-WBC scan of 83
controls did not reveal any false-positive findings in the terminal ileum
(colonoscopy result available in 30 controls). When total colonoscopy or il
eoscopy is not performed or when contrast radiography is negative or unable
to differentiate CD from lymphoid nodular hyperplasia, scintigraphy can de
monstrate the presence of ileitis and/or colitis.